The Basic Consideration on Accident Prevention Strategy for the Operation Executed by Multiple Operators Cooperating in Large Scale Product Lines

This paper shows a new safety system to know the human existence in the machine moving area of large scale product lines. It is very difficult to create such a system because the operator can enter into the machine moving area without pulling out of the interlocking key, and there were not only nominated operators but also non-nominated operators. New concept of the risk management division (I : safe condition, II : uncertain condition, III : hazardous condition) was proposed to evaluate the risk reduction of such system. The risk reduction to the division I can be achieved by direct monitoring devices such as the laser scanning sensor. It can be achieved also by indirect monitoring devices such as the mechanical counter gate. On the other hand, the risk reduction to the division I cannot be achieved only by the plug, key-switch or movable guard.